DTC 58

DTC 58 Transmission Fluid Temperature (TFT) Sensor Circuit Low (High Temperature Indicated):

Transmission Fluid Temperature (TFT) Circuit:

CIRCUIT DESCRIPTION
The Transmission Fluid Temperature (TFT) sensor is a thermistor that controls the signal voltage to the Transmission Control Module (TCM). The TCM supplies a 5 volt reference signal to the sensor on CKT 1227. When the transmission fluid is cold, the sensor resistance is high and the TCM will sense high signal voltage.
As the transmission fluid temperature warms to normal transmission operating temperature 100°C (212°F), the sensor resistance becomes less and the voltage decreases to approximately 1.5 to 2.0 volts. With a DTC 79 also set, check the transmission cooling system.

DTC 58 WILL SET WHEN
^ Signal voltage indicates TFT greater than 151°C (306°F).
^ All conditions are met for 1 second.

ACTION TAKEN (TCM will default to)
The Transmission Control Module (TCM) will use a warm default trans fluid temperature value.

DTC 58 WILL CLEAR WHEN
The fault condition(s) no longer exist.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks for a short to ground or a "skewed" sensor.
2. This test checks for an internal fault within the transmission by creating an open.

DIAGNOSTIC AIDS
Check harness routing for a potential short to ground in CKT 1227.
Scan tool TFT display should rise steadily to about 100°C (212°F) then stabilize.
Refer to "TCM Intermittent Diagnostic Trouble Codes or Performance." PCM/TCM Intermittent Diagnostic Trouble Code or Performance
The temperature to resistance value scale may be used to test the TFT sensor at the various temperature levels to evaluate the possibility of a "skewed" sensor. A "skewed" (mis-scaled) sensor could result in delayed garage shifts or Torque Converter Clutch (TCC) complaints.